Angioplasty entails mechanically widening narrowed or obstructed arteries, such as arteries obstructed from atherosclerosis. An empty and collapsed balloon on a guide wire, known as a balloon catheter, is fed into a vessel to the narrowed location and then inflated to a fixed size using fluid (e.g. water) pressure of about 5 to 30 atmospheres. Typically, a balloon is inflated with sufficient pressure (4-12 atm) to fully expand the stenosis indentation (dumbbell or waist) of the partially inflated balloon. Occasionally, some calcified or highly fibrotic lesions require very high inflation pressures (>14 atm) to expand and eliminate the “dumbbell” appearance of the balloon. Overinflation of the balloon increases the risk of artery dissection. The inflated balloon forces open the obstruction comprised of white blood cell/clot and plaque deposits and expands surrounding muscular wall of the vessel, opening up the blood vessel for improved flow. The balloon is then deflated and withdrawn. A stent may or may not be inserted at the time of ballooning to ensure the vessel remains open.
A bifurcation lesion involves a clinically relevant side branch. Plaque may be located either in both branches or in the main vessel only or in the side branch only. The carina is the flow divider that lies between the main branch and side branch and is the region of high flow and high shear stress.
One angioplasty technique for plaque at a bifurcation is the “kissing balloon” technique. Noncompliant balloons, each having a balloon size that is about same size as the vessel (usually a slightly smaller diameter balloon for the side branch) are used. A balloon is first fed into the side branch so that it protrudes into the side branch and extends into the main branch, but not proximal to a stent. The balloon may be fed into a stent in the side branch. Another balloon (shorter than the main branch stent) is advanced to the main branch so it lies within the main branch but not extending beyond the confines of the stent in the main branch. The balloons are inflated simultaneously. Then the balloons are deflated simultaneously to avoid distortion. In a variation of the basic technique, the side branch balloon is inflated to high pressure (>20 atm, perhaps 24 or 26 atm) and then deflated. Then the main branch balloon is inflated to moderate pressure and deflated. Then, both balloons are simultaneously inflated at low pressure to correct any distortion caused by sequential balloon inflation. These procedures require the ability to independently inflate, maintain inflated, monitor pressure in, and deflate each balloon.
Unfortunately, devices available today do not provide the ability to independently inflate, maintain inflated, monitor pressure in, and deflate each balloon in a kissing balloon procedure. Instead, many practitioners use two separate indeflator devices to inflate, monitor and deflate each balloon independently. While effective, such an approach is not without problems. Managing two separate, but abutting, indeflators in limited available space, with several tubes extending to and from each indeflator, presents challenges to the practitioner and great risk of confusing one indeflator for the other.
Often it is not known if a second catheter is required for a procedure until the procedure is underway. A means for adding a “kissing balloon” module while a procedure is underway is needed.
Thus, what is needed is a device that facilitates independently supplying radiopaque contrast medium through one or more catheters, while independently inflating, monitoring and deflating up to two distal balloons using an expandable device, to which a second module can be added if and when needed.